DESCRIPTION (Applicant's abstract): The objective of this proposal is to use microarray technology to identify mouse genes whose products are involved in the differentiation, maintenance, and survival of retinal ganglion cells. Retinal ganglion cells are essential for normal vision and their loss contributes to major eye diseases in humans. For example, elevated intraocular pressure within the anterior chamber of the eye can trigger enhanced apoptosis in ganglion cells, which in turn leads to glaucoma. Despite their importance, however, the knowledge base of genes associated with retinal ganglion cell formation and survival is rudimentary. Using an arrayed embryonic retinal cDNA library that has recently been constructed, this application proposes to profile gene expression patterns in genetically altered retinas lacking the key transcription factors Brn-3b and Math5. Gene targeting has shown that loss of either Brn-3b or Math5 leads to major defects in retinal ganglion cell formation. The long-term goal is to generate comprehensive gene expression profiles for newly forming retinal ganglion cells and to determine the genetic regulatory mechanisms that lead to retinal ganglion cell differentiation. The specific aims are to: (1) Establish a comprehensive database of expressed retinal sequences from E14.5 mouse retina; (2) Prepare gene chips with known retinal sequences for use in profiling patterns of gene expression in the developing retina; (3) Generate gene expression profiles by comparing genetically altered mouse lines, and different stages of retinal development; and (4) Develop strategies to determine the genetic regulatory networks that lead to the differentiation of retinal ganglion cells.